The invention relates to a device for clamping a disc-shaped tool on a motor-driven tool spindle of a portable machine tool, in particular, a grinding disc on an angle grinder, with a clamping anchor arranged in the tool spindle which has an axial recess, the clamping anchor being axially displaceable relative to the tool spindle and rotationally fixedly connected to the tool spindle, with a clamping flange which is releasable attachable to the free end of the clamping anchor, with an abutment arranged at the tool end of the tool spindle and with a means actuatable by a manual actuating mechanism for releasably pressing the clamping flange against the abutment, thereby clamping the tool between these.
Such a device is known from German Patent 3 405 885. Herein, the clamping anchor arranged in the tool spindle in the form of a hollow spindle is pushed by a pressure spring similarly arranged in the tool spindle so that a clamping flange attachable to the clamping anchor clamps the disc-shaped tool against an abutment on the tool spindle. Therefore, in this device, the clamping force is generated by a spring arranged in the hollow spindle. The clamping anchor can be pushed against the force of the pressure spring by the actuating mechanism so that the clamping flange can be easily released or untightened by hand and, consequently, attachment of the disc-shaped tool is possible without additional tools.
Clamping of the clamping anchor by means of the known spring requires a manual actuating mechanism which is fixedly arranged on the housing on the side opposite the tool and enables a force acting against the spring to be manually applied. This type of actuation, therefore, opposes a compact design of the complete device.
The object underlying the invention is, therefore, to design the known device for attaching a disc-shaped grinding tool which does not require an auxiliary tool for releasing or tightening the tool attachment in as compact a manner as possible and, in particular, in such a way that it is hydraulically actuatable.